An autonomous emergency braking (AEB) system is very effective in avoiding or mitigating crashes including a collision with a pedestrian. The AEB system is a safety device officially included as an item for the safety assessment by European New Car Assessment Program (Euro NCAP) from 2014. The AEB system operates when a preceding vehicle slows down or stops, or when obstacles such as pedestrians suddenly appear. The AEB system avoids collisions or minimizes the damage by generating a warning to a driver or activating the brake on its own without a driver's instruction. There is a statistical result that about 90% of traffic accidents on the road are caused by the driver's concentration loss or carelessness. Experiments have shown that the AEB system can reduce collisions by up to 27% and significantly reduce degrees of injuries even in unavoidable accidents.
Currently Euro NCAP divides the AEB system into three categories. One of the three categories is an AEB system for downtown area, which is used to monitor a distance of less than 10 m from a preceding vehicle in a slow driving mode with the speed of about 20 kilometers per hour (km/h) or less. Another category is an AEB system for suburban area, which mainly monitors the distance of about 200 m in a driving mode with the speed of about 50-80 km/h and significantly reduces risk of accidents even in the slow driving mode in the downtown area. The last category is a pedestrian AEB system, which stops the vehicle when a weak obstacle such as a pedestrian is detected.
If an obstacle is detected, the AEB System prepares to stop the vehicle by, e.g., increasing pressure of a brake system in advance to reduce a gap between a brake pad and a brake disc so that maximum braking performance can be achieved even if the driver steps on a brake pedal late in time. The AEB system has a warning function to draw the driver's attention with a warning sound or an alert first, if there is no action taken from the driver despite the prediction of an accident in advance.